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Modeling the Light Shaping Diffuser

By Anthony Ang, Principal Optical Engineer, Luminit LLC

Anthony Ang – Principal Optical Engineer at Luminit LLC

Degree: B.S. in Optical Engineering from the University of La Verne.

Luminit - Responsible for generating holographic masters, optical design and analysis, and

diffuser model development.

Previous Companies: Newport Thin Film, Xerox Corporation and Autologic Information

International.

Filled various technical, engineering and management roles in the areas of thin film optical

coatings, laser scanners and holographic diffusers.

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About the Author

Founded in 2006, Luminit is a global provider of innovative light management solutions for the

lighting, display, automotive, aerospace, biomedical, and machine vision industries. Our core

expertise includes:

Holographic recording

Micro and nano structure creation

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Luminit’s Background

Light Shaping Diffusers®

Periodic Prismatic Films

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Luminit’s Commercial Products

LED Hiding Power/Homogenization

Precise Beam Angle Control

• 0.5 to 100°

• Symmetrical or Asymmetrical

Improved Uniformity

• Eliminate Striations

• Eliminate Color-over-Angle

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Key Benefits of Light Shaping Diffusers

Substrates: PC, PET, AC, UVT, Glass and UV Fused Silica

Formats: Films, Sheets, Cut Parts, Rolls or Mini Rolls

Thicknesses: 0.25mm to 6mm

Injection Molded: PC, PMMA, Zeonex

Misc.: UV Stable and UL Listed Substrates

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Available in A Wide Variety of Formats and Options

Luminit diffusion technology is based on a very thin microstructure on top of the clearest

substrates available. The transmission efficiency of our thin film and thick rigid diffusers are

practically equivalent!

Surface Relief Pattern

Optical performance is independent of thickness of substrate

Directly applied to substrate without adhesive

Uniform optical performance over all wavelengths/colors

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Luminit Holographic Technology

BTDF data available on our website

❑ LightTools (http://www.opticalres.com)

❑ TracePro, Optis and Zemax

Luminit Diffusers can be found in:

❑ Photopia (http://www.ltioptics.com)

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Luminit Modeling/Simulation

The Bidirectional Scatter Distribution Function (BSDF) is used in scatter terminology to describe the statistical output spread of incident light.

❑ It is a 4-dimensional array, with qi and fi describing the input ray direction and qo and fo describing the output ray direction.

❑ Coordinates similar to global coordinates of latitude (q) and longitude (f).

❑ The function value is typically in units of Radiant (W/Sr) or Luminous (Lm/Sr) Intensity.

❑ The BTDF and BRDF are the respective Transmitted and Reflected portions.

Zemax BSDF is a scatter function which follows the above definition❑ It is a set of tables. Each output table (qo and fo) represents the result of one input direction (qi and fi).

❑ Please read the Zemax Knowledge Based Article ‘How to Use Tabular BSDF Data to Define the Surface

Scattering Distribution’ by Sanjay Gangadhara (2008); Updated by Alissa Wersal

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Some Scatter Definitions

The Luminit LSD scatter model utilizes

the Zemax User Defined type of

scatter model.

A Luminit proprietary function defines

the statistical direction in which the

rays will go.

This allows the shape of the diffusion

to follow the Luminit LSD product.

The Luminit LSD model is designed to

scatter the light at the surface of a

volume object.

The model allows you to select the

catalog angle you desire.

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How the Luminit LSD Model Works

Comparison of Scatter Model Types

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Comparison of Scatter Model Types

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Using the Luminit LSD Model in Zemax Optics Studio - Watch the Video Clip

Some Measured Profiles

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Goniometer ReadingsFrom 1 degree to 30 degrees the shape of the profile isfairly Gaussian.

1 deg

30 deg

60 deg

Some Simulated Profiles

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Zemax OpticStudioFrom 1 degree to 30 degrees the shape of the profile is fairly Gaussian.

1 deg

60 deg

30 deg

Some Simulated Profiles

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Goniometer ReadingsPast 30 degrees the shape transitions into Trapezoidalthen M shaped.

80 deg

60 deg

100 deg

Some Simulated Profiles

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Shape difference, 40 deg LSD 1st or 2nd surface

First SurfaceSecond Surface

Some Simulated Profiles

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Tilting a 60 deg LSD 60deg

Some Simulated Profiles

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Tilting a 60x1 LSD 60 deg

Available Luminit Catalog Angles

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Circular – 0.5, 1, 2, 3.5, 5, 7.5, 10, 20, 30, 40, 60, 80, 100 deg

Elliptical – 15x1, 30x1, 30x3, 30x5, 40x1, 40x10, 50x3, 60x1, 60x10, 60x30, 75x45, 80x50, 90x60, 90x25

Glass circular – 0.5, 1, 5, 10, 15, 20, 30, 40, 50

You can get a copy of the LSD model by going to http://www.luminitco.com/downloads/dll-downloads

Click LumLSD_b3.dll LumGlass_b3.dll

Model Limitations

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❖ BTDF only (Transmission). No Reflection.❖ Only Catalog Angles are available.❖ Rays propagate in the forward direction on object. Surface 1 to 2.❖ TIR will not work.❖ Polarization of light treated as random for transmission amount.❖ Coatings will not work.❖ Curved surfaces will not work properly.

Summary

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❑ Luminit generates the largest selection of diffuser angles and formats.

❑ The LSD model closely simulates the performance of the LSD product.

❑ Luminit is making the LSD model available for Zemax users.

Thank you for downloading this presentation.Contact us at sales@luminitco.com to learn more or go to www.luminitco.com